---
layout: docs
page_title: Inspect the cluster
description: |-
  View the server and client nodes, inspect an individual server or client node,
  list allocations, and review client events from the Nomad web UI.
---

# Inspect the cluster

The Web UI can be a powerful tool for monitoring the state of the Nomad cluster
from an operator's perspective. This includes showing all client nodes, showing
driver health for client nodes, driver status, resource utilization, allocations
by client node, and more.

## View cluster clients

From any page, the Clients List page can be accessed from the left-hand
navigation bar. On narrow screens this navigation bar may need to be opened from
the top-right menu button. The table lists every client in the cluster and is
searchable, sortable, and filterable. Each client row in the table shows basic
information, such as the Node ID, name, state, address, datacenter, and how many
allocations are running in it.

This view will also live-update as the states of client nodes change.

[![Clients List][img-clients-list]][img-clients-list]

## Filter the client view

If your Nomad cluster has many client nodes, it can be useful to filter the list
of all client nodes down to only those matching certain facets. The Web UI has
three facets you can filter by:

1. **Class:** The node of the client, including a dynamically generated list
   based on the node class of each client node in the cluster.

1. **State:** The state of the cluster, including Initializing, Ready, Down,
   Ineligible, and Draining.

1. **Datacenter:** The datacenter the client node is in, including a dynamically
   generated list based on all the datacenters in the cluster.

[![Clients filters][img-clients-filters]][img-clients-filters]

## Inspect an individual client

From the Clients List page, clicking a client node in the table will direct you
to the Client Detail page for the client node. This page includes all
information about the client node is live-updated to always present up-to-date
information.

[![Client Detail][img-client-detail]][img-client-detail]

## Monitor resource utilization

Nomad has APIs for reading point-in-time resource utilization metrics for client
nodes. The Web UI uses these metrics to create time-series graphics for the
current session.

When viewing a client node, resource utilization will automatically start
logging.

[![Client Resource Utilization][img-client-resource-utilization]][img-client-resource-utilization]

## List client allocations

Allocations belong to jobs and are placed on client nodes. The Client Detail
page will list all allocations for a client node, including completed, failed,
and lost allocations, until they are garbage-collected.

This is presented in a searchable table which can additionally be filtered to
only preempted allocations.

[![Client Allocations][img-client-allocations]][img-client-allocations]

## Review client events

Client nodes will also emit events on meaningful state changes, such as when the
node becomes ready for scheduling or when a driver becomes unhealthy.

[![Client Events][img-client-events]][img-client-events]

## Check client driver status

Task drivers are additional services running on a client node. Nomad will
fingerprint and communicate with the task driver to determine if the driver is
available and healthy. This information is reported through the Web UI on the
Client Detail page.

[![Client Driver Status][img-client-driver-status]][img-client-driver-status]

## View client attributes

In order to allow job authors to constrain the placement of their jobs, Nomad
fingerprints the hardware of the node the client agent is running on. This is a
deeply nested document of properties that the Web UI presents in a scannable
way.

In addition to the hardware attributes, Nomad operators can annotate a client
node with [metadata] as part of the client configuration. This metadata is also
presented on the Client Detail page.

[![Client Attributes][img-client-attributes]][img-client-attributes]

## Monitor a node drain

A routine part of maintaining a Nomad cluster is draining nodes of allocations.
This can be in preparation of performing operating system upgrades or
decommissioning an old node in favor of a new VM.

Drains are [performed from the CLI], but the status of a drain can be monitored
from the Web UI. A client node will state if it is actively draining or
ineligible for scheduling.

Since drains can be configured in a variety of ways, the Client Detail page will
also present the details of how the drain is performed.

[![Client Drain][img-client-drain]][img-client-drain]

## View cluster servers

Whereas client nodes are used to run your jobs, server nodes are used to run
Nomad and maintain availability. From any page, the Servers List page can be
accessed from the left-hand navigation bar.

The table lists every server node in your cluster. This will be a small list—
[typically three or five].

[![Servers List][img-servers-list]][img-servers-list]

## Inspect an individual server

Clicking a server node on the Servers List will expand the tags table for the
server node.

[![Server Detail][img-server-detail]][img-server-detail]

## Secure the UI

Depending on the size of your team and the details of you Nomad deployment, you
may wish to control which features different internal users have access to. This
includes limiting who has access to list and manage client nodes and list and
manage server nodes. You can enforce this with Nomad's access control list
system.

By default, all features—read and write—are available to all users of the Web
UI. Check out the [Securing the Web UI with ACLs] tutorial to learn how to prevent
anonymous users from having write permissions as well as how to continue to use
Web UI write features as a privileged user.

## Continue your exploration

Now that you have explored how to inspect the state of your cluster through the
Nomad UI, you will next learn some considerations you should keep in mind when
using the Nomad UI.

[img-client-allocations]: /img/nomad/web-ui/guide-ui-img-client-allocations.png
[img-client-attributes]: /img/nomad/web-ui/guide-ui-img-client-attributes.png
[img-client-detail]: /img/nomad/web-ui/guide-ui-img-client-detail.png
[img-client-drain]: /img/nomad/web-ui/guide-ui-img-client-drain.png
[img-client-driver-status]: /img/nomad/web-ui/guide-ui-img-client-driver-status.png
[img-client-events]: /img/nomad/web-ui/guide-ui-img-client-events.png
[img-client-resource-utilization]: /img/nomad/web-ui/guide-ui-img-client-resource-utilization.png
[img-clients-filters]: /img/nomad/web-ui/guide-ui-img-clients-filters.png
[img-clients-list]: /img/nomad/web-ui/guide-ui-img-clients-list.png
[img-server-detail]: /img/nomad/web-ui/guide-ui-img-server-detail.png
[img-servers-list]: /img/nomad/web-ui/guide-ui-img-servers-list.png
[metadata]: /nomad/docs/configuration/client#meta
[performed from the cli]: /nomad/tutorials/manage-clusters/node-drain
[securing the web ui with acls]: /nomad/tutorials/access-control
[typically three or five]: /nomad/docs/architecture/consensus#deployment-table
